Christian heinzerling



UNITED STATES oHRIsTIAN HEINZERLING, OF BIEDENKOPF, GERMANY.

TAWING HIDES.

SPECIFICATION forming part of Letters Patent No. 231,797,

dated August 31, 1880.

Application filed July 10, 1879. Patented in England December 2 3, 1878.

To all whom it may concern Be it known that I, CHRISTIAN HEINZER- LING, of Biedenkopt, Germany, have invented a new and Improved Method of Tawing Hides; and I do hereby declare that the following is a full, clear, and exact description of the same.

The object of my invention is to furnish an improved process for treating hides for the purpose ot'adaptingthem to the uses ofleather, whereby a superior quality of stock is produced, and at less cost than by the ordinary tanning process.

In carrying my invention into practice, the hides, after the hair has been taken off and soaked in the usual manner, are placed in a solution of alum (from five to ten per cent. of alum) to which zinc dust or cuttings have been added to render the product waterproof. The action of the zinc on the alum produces amorphous alumina, which precipitates on the fiber after the hides have been immersed in the solution a suffieientlength of time, (which is determined bythe texture of the hides,) clogging the pores of the hides. and thereby rendering them water-proof. The hides are now taken out and placed in a solution consisting of one-half to five per cent. of one of the chromate salts, such as ch romateof soda orchromate of magnesia, one to ten per cent. of alum, or in the place thereof an equii'alent amount of sulphate of alumina, and one to ten per cent. of chloride of sodium, in which they are allowed to remain for a longer or shorter time, according to the texture and thickness of the hides being treated. After they have remained in the above solution for several days a small per cent. of yellow or red prussiate of potash may be added to the said solution, or it can be added when the hides are first subjected to the solution. The object of this reagent is to better adapt the surface of the finished stock to be blackened.

In order to permanently fix the ehromic alkalies in the hides that are being treated, they 5 are, after they have been taken out of the acid solution, placed for a shorttime in a weak solution from one to two per cent. of chloride of barium or acetate of lead. The hides are then dried and greased or fatted by dipping them in stearine, paraffine, chrysone or naphthaline, or resin which has been dissolved in benzinc or photogen, and to which a small quantity of carbolic acid or thyme-oil has been added. I

The product thus formed is perfectly waterproof, much more pliable and more serviceable than leather produced by the ordinary tanning process.

I am aware that it is not broadly new to treat hides with chromic alkalies, and I am also aware that leather has been impregnated with baryta to increase its density or weight; but

l/Vhat I claim, and desire to secure by-Letters Patent, is-

The process of tawing hides for the purpose of adapting them to the uses of leather, which consists in first subjectingthe raw hides to a solution of alum and zinc-dust for the purpose of depositing amorphous alumina in the same, then to a solution of one ofthe chromic alkalies mixed with alum, or its described equivalent, and chloride of sodium, then fixing these in the hides by the chloride of barium, or its described equivalent, and finally greasing or fatting the hides, as set forth.

DR. GHR. HEINZERLING.

Witnesses FRANZ WIRTH, FRANZ HASSLAGHER. 

